feat(editor): add WANI JSON round-trip (export/import sidecar)

Closes the JSON round-trip gap on the animation catalog format
shipped last batch. --export-wani-json emits all 8 scalar
fields plus a dual int + name form for behaviorTier so
hand-edits can use either representation. --import-wani-json
accepts either form, falling back to the int when both are
present, and defaults weaponFlags to kWeaponAny when omitted
to preserve compatibility with hand-authored sidecars that
forget to specify it. Verified byte-identical round-trip on
all three preset emitters (starter / combat / movement).
724 documented CLI flags.

tools/editor/cli_arg_required.cpp

@@ -137,6 +137,7 @@ const char* const kArgRequired[] = {
     "--info-magic",
     "--gen-animations", "--gen-animations-combat", "--gen-animations-movement",
     "--info-wani", "--validate-wani",
+    "--export-wani-json", "--import-wani-json",
     "--gen-weather-temperate", "--gen-weather-arctic",
     "--gen-weather-desert", "--gen-weather-stormy",
     "--gen-zone-atmosphere",